Glaucoma is classified into “open angle glaucoma” and “closed angle glaucoma” according to the angle at the junction between the cornea and iris. This junction is mainly responsible for drainage of aqueous humor. The angle is referred to as the anterior chamber angle (ACA). A first step of the process to measure it is to locate the anterior chamber angle region (“angle region”) in an image including the junction, so that classification and measurement can be done. The step of locating the angle region (“angle region segmentation”) is conventionally performed manually, but this is tedious and subject to human error. Techniques have been proposed to do it automatically using edge detection algorithms, but the edge detection step is susceptible to noise in the image. It would therefore be desirable to provide automatic methods for angle region segmentation which are robust to noise. It would further be desirable to provide a process which is capable of generating data indicative of PACG automatically given only a single image of the junction.